Dental blowtorch



May 14,' 1935. E. J. FRANwlcK DENTAL BLOWTORGH Filed July 28, 1952 yg-IIL..

Patented May 14, 1935 DENTAL BLow'roRcH Edmond J'. Franwick, Buffalo, N. Y., assignor to Hanau Engineering Company, Inc., Buffalo,

N. Y., a corporation of New York Application July 28, 1932, `Serial N0. `625,321A

. 12 Claims.

This vinvention relates to improvements in dental blow torches.

'I'he primary object ofthe invention is the provision, of a dental blow torch,'which is simple, inexpensive, and which maybe held in` working; positionand manipulated with one hand so that the other is free for use in handling dentures or doing other dental work; the'device being devoid of rubber pressure-bulbs or other rub- A ber partsv which deteriorate, due to wax` and oil dropping upon the same and perspiration of the hand coming in contact therewith while manipulating the bulb; for examplesuch bulbs as some forms of` dental blow torches Yare provided with for creating pressure and expelling the air through the nozzlev of the torch.

Another Objectis the `provision of a dental blow torchv having 'novel means to secure a sustainedA or intermittently projected flame to .be used. for various dentalk operatic-ns, .and wherein means is embodied to regulate the size of the projected ame, depending on the particular Work; to be performed in theV production, modeling, or'remodeling of dental impressions or other den"- tal objects. n l

Another object is theproduction of a device of this kind which is compact,v easily manipulated, and capable of use for various purposes, although particularlyl designed for various kinds of dental operations. f Y

"A, further object of my invention is the provision of a-fblow'torch havingv a nozzle capable of being moved out; of' line with the llame of the torch so that' the flame ofthe torch may be used to-warm Wax,V and perform other services;4 the nozzle,l when in suc.nposition, preventing Wax dripping thereonto; when being warmed'.

, A. still further object of my invention. is the provision of means allowing various angular changes in the direction of the nozzle so that it may be adjusted. relatively to the plane of. the pressure-inducing device; thus enabling the'nozzle to be positioned inA theA mosty convenient po'- sition for the user to operate the pressure-inducing` device; and direct the nozzle'- toward the object operatedupon.

Other objects of my invention reside in the relative sizes of the passages within the nozzle andthe, relative sizes of the valves controlling such passages, also in the provision oi a pressureinducing device which.v will` create suicient pressure to'` enable a continuous name to issue from the nozzle for; a short period of time without manipulatng4 said: device; the pressure being built upI in the air storagefchamber andi the pressureinducing device being capable of storing up air in said chamber by the time the second cyclel of movement of the pressure-inducing device has taken place; thus,A under constant actuation of the pressure-inducing device, pressure willv be built up in the air storage chamber much faster than it is possible to escape from the nozzle.

With Athe above and lother objects in view to appear hereinafter, my invention consists in the novel features of construction, and the novel arrangement and combination of parts to be hereinafter described and more particularlyr pointed. out in the subjoined claims.

In the drawing: f, v Fig. 1 is a vertical section taken through the blow torch. i l

Fig. 2 is a horizontal section taken on line 2 2, Fig. 1. y n

Fig. 3 is a vertical section taken substantially on line 3-1-3, Fig. 2.

Fig. 4 is a longitudinal vertical section of the air escape nozzle.

Fig. 5 is an enlarged cross section taken on line 5 5, Fig. 4.- v

Reference being had to the drawing in detail, the numeral 6 designates a body or casing which is comparatively light in Weight and may therefore be constructedof any light-weight material,

preferably bakelite, hardv rubber, or `.the like. This casing is hollow in the main and somewhat enlarged at` its upper endrto provide an alcohol removable bottom 9,. f 1

In order to render lthe fuel chamber liquidtight and air-tight so as to prevent evaporation of the fuel, a gasket I is placed between the cover or cap and the upper edge of the wall of the body or casing. The casing is internally shouldered at its lower end to provide a seat for a gasket Il, against which bears the removable bottom 9.

Within the body or casing a block or solid portion I2 is provided which is molded or cast in piece with the wally portions of the casing, and the` casing is provided 4with a lateral extension I3 at one side. The block or solid portion I2 includes a transverse or bridge member I4 which connects opposite portions of the wall of` the casing and a vertical member I5 which extends 2j from the transverse or bridge member to the under side of the cap or cover 8; such members being molded, cored out, and/or machined to provide variousA hollow portions, cavities, and

termed, air-tight.

passages.

The transverse or bridge member I 4 is hollowed out from the laterally extended side of the casing inwardly` -to form-a plunger cylinder I6 and atl its inner end a smaller co-axial .bore I1 is provided which has opposite flat sides and in which is axially positioned va spring-alining pin I8, this plunger cylinder I to provide an upward extension I9 in an air-storage chamber 20 arranged between the transverse or bridge member.|4 and the removable bottom 9, the gasket against which said. bottom bears serving to renderisaid Vair-` storage chamber, or, air chamber'as it may be j yIn order to firmly holdthe bottom in place against the gasket II, a metallic socket-nut 2I'is molded or otherwise, secured in the transverse or bridge member I4,'a securing screwV 22 being passed axially through the removable bottom, the head thereof being entered in a depression 23 formed in a boss 24 extending axially upwardly from said bottom. A gasket 25 is arranged to surround the securing screw between the head of the 4latterandthe inner wall of said depression. With a'view of strengthening said bottom against flexing or breakage, it is internally ribbed, as at r26;, thus, when the securing screw 22 is tightened into the nut 2I,A the gasket 25 will bey compressed i and prevent leakage of air along the screw.' In

this manner theair chamber 20 is rendered perfectly air-tight, except as air is allowed to escape through the passages provided therefor in the transverse or bridge wall I4 andthe vertical member I5; f

`Reiprocably ,arranged within the plunger 4cylinder'l is a piston plunger 21, which is arrangedto be manually depressed and spring-retrieved. The youter open end of the plunger Acylinder is closed by a plunger retainer-plate 28 which has anjopening axially disposed thereiny `with reference Ato lthe plunger cylinder, through "which pis passed: anextension of the `piston -plunger'gaswill presentlyr appear. v

The piston plunger comprises a` central body portion 29, which-may be more particularly referred to as amd-"member, apiston head 30 and afhandle v3I. The rod member 29 is preferably constructed of brass or other suitabley metal and Aprovided between its ends with an enlargement Y y13?." in the formoff an 'upward extension 33 and a vvdownward extension 34; The innery portionY ofthe rod member isvof a size to t intothe bore I1 at the inner endofv the `plunger fcylinder, opposite sides thereof being attened so that it conforms in cross section to `the lcross sectional formation of said bore and thus prevent -rotation of said 'rod member. YSaid inner portion of therod member 'is also yaxially bored out, asat 35, to receive ra helical spring 36 which extends intovthe bore I1 and 4surrounds the pin I8 therein, `said spring bearing at one end against the inner endrof the 'is thus conned within the bore I1 land the bore 35 of the rod member, and by reason of its surrroundingthe pin I8 is prevented `from buckling vwhen thefpiston plunger is movedwnwrdly within the plunger cylinder I6.

suitable material, the circular wall 39 `of which Y surrounds the circular wally of the metallic cupped-member 31, anda retainer disk 4II provided with a hub 4I, which extendsinto the axial opening in the plunger retainer plate-28. The metallic cupped-,member 31 and the cupped friction or packing member 38 are slipped over the rod member 29 from its outer end, said metallic cupped-member bearing against the enlargement V32 of said vrod member. Said rod 'member is screw-threaded alongI a portion of its length and -has theretainer disk 40 threaded'thereon, said disky serving to clamp the cupped-members 81 and 38 firmly onto the rod member. The portion of the rod member extending outwardly from `the screw-threaded `portion thereof is smooth rod member 29, the inner end wall of vthis axial bore having lugs 44 adapted' to enter the notches 42 in saidsrod member to prevent turning, of the handle.

Extending from the outer. end of .the rodniember ,inwardly to within ashort distance of the bore 35 at thev inner end thereof is an axial airintake passage 45 which is enlarged at its outer end and screw-threaded, and 'passed axially through the outer end of the handle so as to project into the shank thereof is a securing screw 46, -which is threaded into vthe enlarged outer end portion of 'said vair-intake passage; thusthe handle is securely fastened to thefrod member 29 of the piston plunger.`

, The upward extension of Ythe enlargement 32 of theV rod member is hollowed out to .form a Valve-pocket 41, which opensinto the plunger cylinder and is Vprovided with a valve seat at its loweror inner end and.- connected with the air-intake passage 45. by an air-duct, 48. Disf posed within said: vvalve pocket is a spherical ball Valve 49 serving to close the air-duct 48, and arranged insaid'valve pocket is Aa helical spring 58 which bears at one end against the spherical valve 48l and at its other end against the circular wall of the metallic cupped-member 31 of the piston head 30, saidspring serving to normally as at 53. The lower end of this bore is screwthreaded, and connecting the upper end thereof with a high vpoint ofthe air chamberv20 is an L- shaped air passage 54, one legof which opens axially intothe upper end of this bore. t

A valve plug 55. is fitted into said bore 53 and has a screw-threaded portion 58'threaded .into

the threaded portion of said bore;` it being alsol provided with an enlargement or head 51 at its lower end equippedwith a diametral slot 58 to f acores-s receive. a screw-.driver or other tool'= permitting ptacementwithinf, or detachment: ot-4 the valvephigftrom they boreli Between the enlargement or head l51 and the under sideorf the transverse or bridge. member Mja, gasket 59. is arranged, thus preventing leakage ofy airy alongv said valve-plug. A. gasket, 53, is. also; placedbet-ween the, inner end otsatd valve-plug and the inner end Wall of said ble;

rimmed inv theupper-end of' this valveplug isi-a valve. pocket 60 somewhat larger in diameter than the legofthe L-shaped` or angular Mage. 54; the lower extremity of` which opens into said: pocket.. The valve-plug 55;- is reduced diameter betweenv its. endsy along a. portion of its length. to. provide', an annular air space 6l between it and its surrounding wall, and anl L- shaped or angular airpassage 62' is. formed in the valve-plug; This angular passage is of comparatively small diameter and one leg thereof is `initiallydisposed within the valve-plug andi opens inlJQ-the Ivalve pocket Bil-while the other. leg thereof is arranged withinsaid valve-plug and opeasiintofsaid annular lair space 61| With the, valve pocket 60 is aspherical valve i3 whichvnorma-lly is-seated against the inner end wall; ot' SaidY pocket andY closes, the upper end of axially-disposed; leg of air passage 6 2.A Arwit-hino said valve. pocketr 60 is a helical spring-g bearing at one end against said spherical valve and; at. its other end. against the: inner end Wall' of; the; borel 53. aroundl ther leg of the -k-Shanedf. Or-,Mxculerpassage 54 opening into seid valyepecket- Aselearlx-'shewn in Fic; 2; the. annular airspace @t iis-,connectedwithl the innerend of the plunger cylinder i6 bi1-eport 0r passage 65..

The cover or cup 8 is; provided with an integral mardis-.directed boss: ort-extension 66 intowhich is; a 6;1, the upper end this, buehine: terminating a; distance from, the

endef saidbossi or extension.

As'- clearlyshown in- 1-,i the; vertical member |61 is; tapered upwardly-:z it; beine.y formedcomparatively' wide in one. direction and narrow in the: ethenxet: beine completelysurroundedwith the fuel-withintheiuelichamber-1i. Formed-onthe und?? side ofv the cover.v o r capl 8. isan endless,` rib SQ;A whieh forms: elongated depressionto` receive the upper' end., of` the vertical memberU t5. A. gasketj is arranged: within, said depression and-,interposed between-,the cover oli-cap. S-and-the upper end of said vertical member. The cover; or is secured tothe: surrounding-'Wall ofthe fuel chamber by. means; of` screws 10,1 anditis, also secured.I to the vertical meinber- |l5 by means--v of Arrangedfwithinthe boss cir-'extension 65 ofithe cover or cap is a nozzle member 12` comprising 1 a, bodyY portion 13- of 'IT-formation tol provide a horizontal-member Hand a1 vertical or depending member adapted., to nt loosely;` within4 thefupper portiony of said. boss: or extension. This body portionisf-also constructed of bakeliteor similar materiahandmoldedinto the vertical; or depend.- ing portion thereof isz-a., metallic sleeve 1-6 having af, projecting, lower portion` taperingdownward- 1yr-from,- the lower` end ot; the-vertical` or depending member 15.

Withinthe horizontal member 14 isa metal.- lic; sleeve 1,1,l which projects, from. one en d of said member and. has-y screw-threaded thereon. an. air-escape nozzle 18. The passage in the sleeve 111. isy connected with the passage, of the; 15-

duet. 1B formed in the wall. or the sleeve 1:1, and; the passage through the air-.escape nozzle 1li` is axially aimed with thepassage in said-sleeve 11. The passage in the sleeve 111: is enlarged at one end, as at 83;, it beingscrew-threaded adjacenty said' enlarged -por'- f tion to receive an air-regulating device 8l', which is. in the form of a regulating screw enlarged along its outer end to form a shoulder 82 which rests againstthe-'shouldcr 83 inthe sleeve formed by. enlarging. the end of the: passage therein. Said regulating screwis provided witha knurled head 84 so that it can be easily adjusted'. Both the threaded portion of' said` regulating|` screw and the enlargement thereof are 'flattened atone side along their entire lengths, as at 85, so that an airescape passage 86; isr formed. between the screw' and the surrounding Wall of' the sleeve 1:1, Said passage is closed' against the escape.v of air when the shoulder 82 of the screw bears against the shoulder 83 of the sleevel 111. Mone particularly expressed, this adjusting screw may be termed an air-adjusting valve, since' the enlarged portion of the screw servesas. avalveand the shoulder 83 in the sleeve 11 as aseat for-said valve; The space or passage 86. formed between the at portions of the-screw and the cylindrical wall of the sleeve 11 maintains a definite area regardless ofthe positionr of the screwor valve within the sleeve, and the distancethe shoulder or Valve 8-2 is spaced from. the shoulder or seat 83.-` determines the amount of" air allowed to ese cape. This air-regulating device provides-,adouble closure against the escape of air.; rst, byreelson ofi'theenlarged. portion of the screw, or the valve proper as it may be termed-bearing against the shoulder or valve seat 83 of the sleeve 11 and, secondly., by reason. of the headlw bearing against the end. of: said sleeve. I-rdeSiredf a gasket may be placed between the head 8.42,-and theT endi of the adjacent end of the sleeve 11.;

The metallic bushing 61: molded into.l they up;- wardly-directed boss. or extension. of the. cover is provided` with an axially downwardly-.tapering bore 81 intowhich the tapered-lower end; of the sleeve 16, in, the nozzle member f-isradapted.. to. t,

said: nozzle member being thus rotatably.- fitted in: said boss or extension, and/by reason off the 'tapered' portion of the sleeve Vlifijtting in the1 taf- .pered bore of the bushing 61g anLair-tightcomnection ismade at this point. i n l. Conduit connection; is provided between the1 'air chamber 2.0: and the bushing. 6i1,.the .latter hw.'-

'ing the lower-end off its bore reduced in: diameter and opening through. the gasket 'into a depresi- .sion 88 formed in the top.z of theA vertical member l5, said: depression rangingin'the direction of the greatest Width of saidy vertical member; and.

having a passage 89. openingv thereinto: which leads downwardly.y throughsaid: vertical member into the air chamber 2li.'

Wit-h a view of. retarding` the escape of air from:l the air chamber 2lil and to setl upl friction in; the passage. of: the air` to the nozzlemember, av tube Bllis threaded into the lower end; of the `passagefllll. 'Extendingjinto the lower endzof this :fjgMoldedintothe cap or cover `at one side there- 1rof, is'a metallic bushing 92 'into which is thread- .ed a wick-retaining ferrule 93, and-between an .enlargement of which ferrule and the upper end of said' bushing a gasket 94 is arranged, a wick being retained in. said wick ferrule and extending downwardly therefrom into the fuel chamber 1.. The cover or cap 8 also has a second metallic yto place the device in position for use, to grasp lthe device in .one hand, placing` the thumb or .other --portionorportions'of the hand against the handle 3| of the piston plunger. Upon depressing the piston plunger 21 against the action of" the helical .spring 36, air within the plunger .cylinder I6 is forced. through the port or passage `lii'and enters ,the annularl airr space around the valve plug.55. From this annular air space. the 'air is .directed through the L-shaped or angular air .passage `62 in said valve plug, upwardly zthrough the valve pocket 60, from which it enters zthel L-shaped or angular passage 54 and escapes intothe air chamber or air storage chamber 20. From this chamber the air escapes through the tubular coil 9| and passes upwardly through the -tube 90,through.the passage 89 and thedepressionv 88 connected therewith, and escapes out `throughxthe bushing 61, entering the sleeve 16` of .the nozzle member. From this sleeve the air out through the air-duct 19 and enters the passage. in .thesleeve 11; escaping from the air-.escape nozzle 18. This nozzle, as clearly shown in Fig. 1, terminates at'its outer end in close proximity to and at aplane above the outer `end :of the wick 95, and thus when said wick is lighted-directs the flame laterallyagainst a denture or any other object operated upon.

While the torch is held in the hand andy pressure relieved from the handle 3|, the helical spring 36 will force the piston plunger in an outward' direction, andduring such action allow vair tol enter thefair-duct 52 in the hollow shank of the handle, which then passes through the airduct.52 inthe rod member of the plunger and along the air-intake passage 45 therein; the inrushing air lifting the spherical valve 49 toallow Athe airto enter the plunger cylinder vso that it may be .forced into the air storage chamber 28 in the manner described, and from the latter out "'throughthe nozzle 18.v

It will bey apparent from the foregoing, that by positioningzthe piston'plunger and its receiving cylinder-the pressure-inducing device as it may 'be termed-between the fuel andv air storage Ychamber,a compact symmetrical torch" is produced-without .connected adjuncts; the. torch being one that can be conveniently taken in one `Ihand and easily manipulated, particularly since theV axis of the vpressure-inducing device is at right-angles to the axis of the complete torch and practically connedwithin the body portion of the'torch. By reason of this arrangement the torch can begrasped in a manner similar'tothe .way the butt of a gun is grasped, and the pressure-inducing device operated with the foreiinger of the hand in a manner similar to that of actu- 'atingthe trigger of a gun. It will be apparent therefore that when grasping the torch in .one

hand .the other 'is Vfree-for use, andthe-arrangement described enables the operator to. direct :the-flame to the desired point more 'effectively .than would otherwise be possible. f 1

When using the tubular coil 9|, which may be termed a restricting tube,"the air will enterithe `air-storage chamber 28 faster than it can escape `throughthe nozzle 18, withthe result that-the regulating device 8|, so that the vflame from the wick can be projected to any 'desired degree, it

`being simply necessary to slightly. imscrewfth'e :screw member of said device so as to unseat the shoulder or valve 82 thereof from the shoulder or -seat 83 in the sleeve 11, thus allowing part ofthe .air entering said `sleeve to 'escape through-the space 86 formed between the scre'w'member of the air regulating device and the wall'of ;the sleeve, which latter serves to form part ofthe air regulating device. Should an intermittent flame be desired, the piston plunger is manipulated intermittently so as to allow the air accumulating Vin the air storage chamber toescape therefrom before another charge of air is deliveredinto the air-storage chamber, or the flame maybe projected intermittently by. opening the regulating device 8| sufficiently to preventthe lbuild'ingi up of the air pressure within the air chamber.`

A.intermittently projected flame can be easily provided by the operator under either of the two methods `mentioned for the same.l 1

In rView of the fact that the vertical depending member 15 of lthe air-escape fnozzle is loosely vfitted into the upper end of theboss or'exten'sion 66, this nozzle can be rotated to an'y vdesired angle so that its outer Vor escape endl is lspaced desired distance from the flame of the wick; thus permitting the deviceto be convenientlyused for warming or heating wax, and for other purposes; and by reason of the projecting lower portion of the metallic sleeve v16 being tapered and fitting into the tapered bore of the bushing $1-, air-'tight connection is maintained atV all timesbetween these two elements, regardless 4o1 the angular position to which the air-escape nozzle maybe rotated. i l Y It` will also be apparent that changes construction, and arrangement of parts 'may' be resorted to, and modifications thereof made, without departing fromk the `spirit of my 4{inven- 4tion asset out in the appended claims.

WhatIclaim is: i n g -l. Adental torch, comprising a casingl having `a plunger cylinder between its ends with its axis at an angle thereto, an air chamber and-a fuel chamber separated by said plunger cylinder, a

piston plunger within said plunger cylinder, con'- duit connection between said plunger-cylinder and said air chamber, an air-escape nozzle',A conplunger cylinder between its ends with fits axis at an angle thereto, an air chamber vand a fuel chamber separated by said plunger cylinder,'a

`piston plunger 'within` said cylinder', conduit connection between said plunger cylinder and said air chamber, an air-escape nozzle, conduit connection between said air chamber and said airescape nozzle including means to restrict' the passage of air to said nozzle at a pressure below that at which air is forced into said air-chamber under manipulation of said piston plunger, and means for maintaining a flame in the pathI o-f the air escaping from said nozzle.

3. A dental torch, comprising ,a casing having pressure-inducing means therein with its axis at an angle to the axis of said casing, an air chamber, and a fuel chamber separated from said air chamber by said pressure-inducing means, an air-escape nozzle without said casing, and a passage in communication with said pressureinducing means and leading to said nozzle, said passage having a portion diminished in size from at least another portion thereof.

' 4. A dental torch, comprising a casing having a plunger cylinder therein at a right angle to the axis thereof and formed integral therewith, a piston plunger reciprocably arranged within said plunger cylinder and having an operating element projecting from said casing, an air-escape nozzle without said casing having conduit connection with said plunger cylinder, and means for maintaininga flame in the path of the air escaping from said nozzle.

5. A dental torch, comprising a casing having a plunger cylinder formed therein with its axis at an angle tothe axis of said casing and wholly confined within the walls of said casing, a piston plunger within said cylinder manually depressible and automatically retrievable, an air-escape nozzle extending from said casing and having conduit connection with said plunger cylinder, land means for maintaining a flame in the path of the air escapingfrom said nozzle.

6. A dental torch, comprising a casing having a f solid portion between its ends connecting the wall thereof at opposite points and providing a fuel chamber thereabove and an air chamber therebelow, said casing being open at the top and bottom, a removable closure member for closing the bottom of said casing, a removable coverr closing the top of said casing, pressure-inducing means disposed within said solid portion and having an operating element extending out through said casing, an air-escape nozzle mounted on said cover, conduit connection between said air chamber and said pressure-inducing means and between said air chamber and said air-escape nozzle, and means for maintaining a flame in the path of the air escaping from said nozzle.

'7. A dental torch,lc0mprising a ca-sing having4 a bridge wall between its ends and a vertical member extending upwardly from said bridge wall, said `bridge wall and casing forming a fuel chamber thereabove and an air chamber therebelow, said bridge wallhaving a plunger cylinder therein, a piston plunger mounted for reciprocation in said plunger cylinder, a valve-controlled air passage in said wall leading from said plunger cylinder to said air chamber, a nozzle member mounted on said casing, said bridge wall and vertical member having a passage extending therethrough leading from said air chamber to said nozzle member, and means for maintaining a flame in the path of the air escaping from said nozzle member.

8. A dental torch, comprising a casing having a bridge wall between its ends and a fuel chamber above said bridge wall, said casing being open at the bottom, a removable closure member applied to the open bottom vof said casing in an air-tight manner and establishing an air chamber between the same and said bridge wall, a.

securing element passed through said bottom and extending upwardly into said bridge Wall, pressure-inducing meansl arranged within said bridge wall, an air-escape nozzle mounted on the top of said casing, conduit connectionbetween said air chamber and said pressure-inducing means and between said air chamber and said air-escape nozzle,` and means for maintaining a flame in the path of the air escaping from said nozzle.

9. A dental torch, comprising a casing having a fuel chamber and an air chamber spaced apart, a plunger cylinder within said casing separating said fuel chamber from said air chamber, a piston plunger in said plunger cylinder having an operating element extending outwardly from said casing, a valve-controlled passage wholly within said entered in the screw threaded portion of saidV passage and having an enlargement forming an inwardly-facing shoulder, the enlargement of said screw being entered in the enlargement of said passage and the inwardly-facing shoulder of said screw being adapted to bear against the outwardly-facing shoulder of said passage, the screw-threadedportion of said screw and the enlargement thereof being cut away at one side to form an air-escape between said screw and the wall of said passage, said screw having a head at its outer end.

11. A'dental torch, comprising an exterior boss provided with a bore therethrough opening-to the interior of said torch and having said bore tapered along ya portion of its length, and an airescape nozzle having a portion loosely fitted into said boss and being provided with a tapered extension beneath said loosely fitted portion entered into the tapered portion of the bore in said boss, said nozzle being maintained in air-tight position within said boss by the frictional t of the tapered portion thereof within the tapered portion of the bore of said boss.

12. A dental torch, comprising a casing wholly enclosing a fuel chamber and a plunger cylinder, a piston plunger reciprocable within said plunger cylinder and provided lwith an voperating element extending outwardly from said casing at an angle thereto, an air-escape nozzle having conduit connection with said plunger cylinder, and means for maintaining a flame in the path of the air escaping from said nozzle.

EDMOND J. FRANW'ICK. 

